Vibration gyro element, gyro sensor, and electronic apparatus

Abstract

A vibration gyro element includes drive vibrating arms and detection vibrating arms at the opposite side, and has a first detection mode in which the drive vibrating arms flexurally vibrate oppositely to each other in an out-of-plane direction in an opposite phase to an action direction of Coriolis force and the detection vibrating arms flexurally vibrate oppositely to each other in the out-of-plane direction in an opposite phase to that of the drive vibrating arms, and a second detection mode in which the drive vibrating arms flexurally vibrate oppositely to each other in the out-of-plane direction in the same phase as the action direction of the Coriolis force and the detection vibrating arms flexurally vibrate oppositely to each other in the out-of-plane direction in the same phase as that of the drive vibrating arms.

What is claimed is: 
     
       1. A vibration gyro element comprising: a support part; a first drive vibrating arm, a second drive vibrating arm and a third drive vibrating arm extending from the support part in juxtaposition to each other in this order; and a first detection vibrating arm, a second detection vibrating arm and a third detection vibrating arm extending from the support part toward an opposite side from the first through third drive vibrating arms in juxtaposition to each other in this order, wherein the vibration gyro element having a drive mode in which the first and second drive vibrating arms flexurally vibrate oppositely to each other and the second and third drive vibrating arms flexurally vibrate oppositely to each other in an in-plane direction along front and rear principal surfaces thereof at a predetermined drive resonance frequency fd, a first detection mode in which, by Coriolis force acting due to rotation around extension directions of the first through third drive vibrating arms, the first and second drive vibrating arms flexurally vibrate oppositely to each other in an out-of-plane direction crossing the front and rear principal surfaces thereof, the second and third drive vibrating arms flexurally vibrate oppositely to each other in the out-of-plane direction, the first and second detection vibrating arms flexurally vibrate oppositely to each other in the out-of-plane direction, the second and third detection vibrating arms flexurally vibrate oppositely to each other in the out-of-plane direction, the first detection vibrating arm flexurally vibrates in an opposite phase to that of the first drive vibrating arm, the second detection vibrating arm flexurally vibrates in an opposite phase to that of the second drive vibrating arm, and the third detection vibrating arm flexurally vibrates in an opposite phase to that of the third drive vibrating arm at a predetermined first detection resonance frequency fp 1 , and a second detection mode in which the first and second drive vibrating arms flexurally vibrate oppositely to each other in the out-of-plane direction thereof, the second and third drive vibrating arms flexurally vibrate oppositely to each other in the out-of-plane direction, the first and second detection vibrating arms flexurally vibrate oppositely to each other in the out-of-plane direction, the second and third detection vibrating arms flexurally vibrate oppositely to each other in the out-of-plane direction, the first detection vibrating arm flexurally vibrates in the same phase as that of the first drive vibrating arm, the second detection vibrating arm flexurally vibrates in the same phase as that of the second drive vibrating arm, and the third detection vibrating arm flexurally vibrates in the same phase as that of the third drive vibrating arm at a predetermined second detection resonance frequency fp 2 , wherein the predetermined drive resonance frequency fd, the predetermined first detection resonance frequency fp 1  and the predetermined second detection resonance frequency fp 2  fulfill: fp 1 <fd<fp 2 , and 0.7×(fd−fp 1 )≦fp 2 −fd≦1.3×(fd−fp 1 ). 
     
     
       2. The vibration gyro element according to calim  1 , wherein a width Wb of the support part with respect to a length Ld of at least two of the first through third drive vibrating arms is set in a range of Wb/Ld≧2. 
     
     
       3. The vibration gyro element according to  claim 2 , wherein the width Wb of the support part with respect to a length Ld of at least two of the first through third drive vibrating arms is set in a range of Wb/Ld≧2.5. 
     
     
       4. The vibration gyro element according to  claim 3 , wherein the width Wb of the support part with respect to a length Ld of at least two of the first through third drive vibrating arms is set in a range of Wb/Ld≧3.3. 
     
     
       5. A gyro sensor comprising the vibration gyro element according to  claim 1 . 
     
     
       6. A gyro sensor comprising the vibration gyro element according to  claim 2 . 
     
     
       7. A gyro sensor comprising the vibration gyro element according to  claim 3 . 
     
     
       8. A gyro sensor comprising the vibration gyro element according to  claim 4 . 
     
     
       9. An electronic apparatus comprising the vibration gyro element according to  claim 1 . 
     
     
       10. An electronic apparatus comprising the vibration gyro element according to  claim 2 . 
     
     
       11. An electronic apparatus comprising the vibration gyro element according to  claim 3 . 
     
     
       12. An electronic apparatus comprising the vibration gyro element according to  claim 4 .